The Council for the West has called on politicians to find solutions to the decision by Aer Lingus to end its Shannon-to-Heathrow flights.
The voluntary body, which numbers Irish bishops among its patrons, said business and tourism in the region will be hit by the decision, with the consequent loss of jobs and opportunities.
In a statement following the airline's announcement today, the council said the route to Heathrow provided a very important strategic connection to South America, Australia, Africa, Japan and China, and that its loss will be "a major blow to the whole West region".
It said the ending of the four daily flights between Shannon and the London airport would also worsen gridlock on the roads to Dublin airport.
Spokesman Ray O'Donoghue said: "The Government are still significant shareholders in Aer Lingus and must know that the decision will adversely affect this region. Jobs in business and tourism are being placed in jeopardy.
"For that reason we call on politicians of all parties to work together to find a solution before serious damage is done."
The Council for the West was set up by the bishops of the region and is a voluntary, independent, non-political body that monitors and reports on the socio-economic state of the west and acts as a lobby group promoting the development of the region.
Chairman of Shannon Development John Brassil called for an immediate review of the decision to terminate the Shannon-Heathrow service.
"Given the critical nature of the links, we are astounded that Aer Lingus has taken this decision to withdraw from Shannon and move to Belfast. The switching of the Shannon Heathrow slots constitutes a fundamental breach of trust by Aer Lingus in respect of Shannon and the West of Ireland. As the tourism authority for the Shannon Development Region and with an industrial client base around the Shannon Region we are extremely disappointed with this decision," he said.
However, the Consumer Council of Northern Ireland welcomed the move by the airline to Belfast and said it injected much-needed competition for air passengers.
Head of consumer affairs Eddie Lynch said it was "a welcome and significant boost for business and leisure travellers" and he congratulated Belfast International Airport for adopting a "long-term, strategic approach to securing a thriving and sustainable marketplace for air travel".